Patent GB-745968-A (GB)
Title: Improvements in or relating to shell moulding apparatus
Inventor: STONE VINCENT OLIVER
IPC: B22C23/00
Filed: 1954-01-11
Abstract: 745,968. Moulding-processes. GLACIER METAL CO., Ltd. Jan. 11, 1954, No. 802/54. Class 83 (1). A shell-moulding apparatus comprises a tipping-frame 5, 6 pivoted in bearings 3, 4 on a fixed structure 1, 2, an investment bin 12, carried by the tipping-frame, a member 11 removably supporting a pattern-plate 24 and pivoted by gudgeon-pins 9, 10 in bearings 7, 8 in the tipping-frame so that in one pivotal position of the member 11, the investment side of the pattern-plate is exposed to allow a shell thereon to be ejected, and in another pivoted position the investment side faces the bin, means for moving the bin 12 along the tipping- frame until the investment side of the patternplate is enclosed in the bin, and means for then pivotally inverting the frame, bin, and patternplate supporting member 11 as a unit to allow the investment mixture 13 to fall on to the pattern-plate 24, and subsequently reinverting them prior to separating the bin from the pattern-plate and returning the pattern-supporting member 11 to its ejection position. The bin 12 has rollers 14 running in channels 15 in plates 5, 6, and is raised and lowered by a hydraulic-ram in a cylinder secured to the tipping-frame and actuating arms 20 pivoted at one end to the frame and connected at the other end to gudgeon-pins 22 pivoted to the bin, which is locked in its lower position by pins 53 thereon engaging slots 54 in parts 55 of fixed structure 1, 2. The pattern-plate 24 is slid into grooves 23, cut in the supporting-member 11, and the shell 38 formed on the pattern-plate is ejected by stripper-pins 26 fixed to a stripper-plate 27 having a part 37 with an undercut slot engaged by the head 36 of the piston-rod 34, of a hydraulic cylinder 31 rigid with the member 11. The downward movement of the stripper-plate 27 is limited by the heads 29 of guide rods 28 attached to the pattern-plate. The upward movement of the rod 34 ejects the shell 38, while its downward movement finally clamps the pattern-plate-assembly; a spring 39 between a lower piston-rod 35 and a fixed part 40 being loaded so that when there is no pressure in cylinder 31 the head 36 is a loose fit in the slot in the member 37 and the pattern-plate can easily be withdrawn from the grooves 23. The tipping-frame and the member 11 are turned by two opposed hydraulically-operated pistons interconnected by a toothed rack 46 engaging a pinion 48 on a hollow shaft 49 supported in bearing 4 and provided with an internal concentric bearing supporting the pivot-pin of the part 6 of the tipping-frame. A second pinion 51 secured to shaft 49 engages a pinion 52 secured to the pivot 10 of the member 11. In operation, the member 11 is initially in its " ejection " position and the bin 12 in its locked lower position, Fig. 1. A pattern-plate assembly complete with shell is removed from an oven and slid into position in the grooves 23, and the pivoted rod 34 actuated to eject the shell. The hot pattern is cleaned and sprayed with a parting fluid and the rod 34 actuated in the opposite direction to clamp the pattern-plate assembly. The rack 46 is then actuated and, since the tipping-frame is locked by the bin 12, the pinion 48 acts through pinions 51, 52 to invert the member 11 so that the investment side of the pattern-plate 24 faces the bin 12 which is then moved upwards until its edges contact the plate 24, Fig. 4. The rack 40 is now actuated in the opposite direction and, since the member 11 cannot rotate relative to the tipping-frame and the bin is no longer locked to the fixed structure, the tipping-frame rotates about its axis to invert the bin 12 over the pattern-plate and allow the investment mixture 13 to fall thereon and form a partly cured shell. The tipping-frame is then reinverted, the bin 12 lowered into its locked position and the rack again operated to rotate the member 11 into its ejection position (Fig. 1). The pressure in the cylinder 31 is relieved to enable the pattern-plate assembly to be removed for curing in an oven.